| 摘要 |
PURPOSE:To enable opening and closing tests of valves without changing steam inflow into a steam turbine by providing a working mechanism for main steam control valves with test cylinders as well as detectors of test positions. CONSTITUTION:Both test cylinders 26a- and detectors of test positions 27a- are provided for respective valves for a working mechanism of main steam control valves 3a-3d together with a main steam control valve oil cylinder 19. Each valve is opened consecutively, for a valve test, to a test position from the full opening position by means of a test cylinder and as soon as a detector 27a locates the test position, the valve is put back to its original opening. At this moment, valve flow characteristic is saturated at the full opening and consequently a valve test is possible without changing steam inflow into a turbine. |
